The proposed project is a history of health risks in American society and medicine since World War II. While there is considerable societal and medical debate about particular health risks and prevention practices, neither the dimensions nor implications of a "health risk revolution" have been fully appreciated. Interventions to reduce the risk of new disease or the probability of events associated with existing disease already occupy a central role in pharmaceutical use and expenditure. Risk ideas and practices have radically transformed and blurred the experience of risk and chronic disease. In the clinic, medical marketplace, and in individual decision making, there has been a largely ignored transformation in how efficacy has been understood and constructed. This project aims to: (1) provide the social and historical context for health risk intervention in modern American society and medicine;(2) contribute to the intellectual foundations of more effective disease prevention policies and practices;and (3) expand the boundaries of socio-cultural scholarship in health by combining materialist and constructivist methodologies. The project will combine research into the history of particular health risks with a synthesis of a large amount of the existing social science and medical literature on health risks. I will compare and contrast the history of different health risks and the medical and societal responses they have elicited. The resulting book of essays will be organized by theme rather than by the history of any particular health risk or set of risks. I expect this project to produce specific findings that will contribute to all three aims. It will delineate the ways demand for health risks has been produced, trace the transformation in medical and lay understanding of the efficacy of risk interventions, and analyze historical changes in the experience of risk and intervened-in chronic disease. The project's results should contribute to a broad societal debate about whether we should regulate research on health risks and the way risks are publicized and made objects of prevention practices. This project's demonstration of the ways values and interests have shaped prevention practices should also suggest greater inclusiveness in policy making by individuals and groups with a legitimate stake in the outcomes of prevention policies.